The insulin receptor is dependent on magnesium and hypomagnesemia is associated with increased insulin resistance and decreased insulin secretion and action. Recent data suggest that hypomagnesemia may play a role in development of type 2 diabetes. Kidney transplantation patients have low plasma magnesium levels, partly due to treatment with calcineurin inhibitors. However, the role of magnesium in the development of post-transplant diabetes mellitus (PTDM) is unclear.

The present study addresses, whether hypomagnesemia is feasible to reverse by oral administration of magnesium.

The investigators wish to investigate whether oral magnesium supplementation is sufficient to increase magnesium levels in kidney transplant recipients, and if supplementation improves glycemic parameters as measured by an oral glucose tolerance test (OGTT).

Inclusion Criteria:

• Kidney transplant recipients more than one year after transplantation
• Hypomagnesemia (< 0.7 mmol/L)
• Age ≥ 18 years and able to give written informed consent

Exclusion Criteria:

• Current treatment with magnesium containing medication or supplements
• Current medical treatment for diabetes
• Conditions impairing magnesium absorption from the gastrointestinal tract (e.g. short bowel syndrome, chronic pancreatitis)
• Subjects with primary non-graft function and subjects with need of dialysis therapy >2 months or graftectomy at any time point after transplantation